Chapter 10

Some photosynthetic bacteria (e.g., purple sulfur bacteria) have photosystem I but not II, while others (e.g. cyanobacteria) have both PSI and PSII. Which of the following might this observation imply?a. Photosystem II must have been selected against in some species.b. Photosystem I must be more ancestral.c. Photosystem II may have evolved to be more photoprotective.d. Cyclic flow must be more primitive than linear flow of electrons.e. Cyclic flow must be the most necessary of the two processes.

Cyclic electron flow may be photoprotective (protective t light-induced damage). Which of the following experiments could provide information on this phenomenon?a. using mutated organisms that can grow but that cannot carry out cyclic flow of electrons and compare their abilities to photosynthesize in different light intensitiesb. using plants that can carry out both linear and cyclic electron flow, or only one or another of the processes, and measuring their light absorbancec. using bacteria that have only cyclic flow and look for their frequency of mutation damaged. using bacteria with only cyclic flow and measuring the number and types of photosynthetic pigments they have in their membranese. using plants with only photosystem I operative and measure how much damage occurs at different wavelengths

A: using mutated organisms that can grow but that cannot carry out cyclic flow of electrons and compare their abilities to photosynthesize at different light intensities

Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants?a. They serve as accessory pigments.b. They dissipate excessive light energy.c. They cover the sensitive chromosomes of the plant.d. They reflect orange light.e. They take up toxins from the water.

In thylakoids, protons travel through ATP synthase from the stroma to the thylakoid space. Therefore the catalytic knobs of ATP synthase would be locateda. on the side facing the thylakoid spaceb. on the ATP molecules themselvesc. on the pigment molecules of PSI and PSIId. on the stroma side of the membranee. built into the center of the thylkoid stack (granum)

Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?a. The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.b. The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water and electrons to the light reactions.c. The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP.d. The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provide the light reactions with water to split.e. There is no relationship between the light reactions and the Calvin cycle.

A: The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.

What is the primary function of the Calvin cycle?a. use ATP to release carbon dioxideb. use NADPH to release carbon dioxidec. split water and release oxygend. transport RuBP out of the chloroplaste. synthesize simple sugars from carbon dioxide

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants.

Produces molecular oxygen (O2)a. light reactions aloneb. the Calvin cycle alonec. both the light reactions and the Calvin cycled. neither the light reactions nor the Calvin cyclee. occurs in the chloroplast but is not part of photosynthesis

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants.

Requires ATPa. light reactions aloneb. the Calvin cycle alonec. both the light reactions and the Calvin cycled. neither the light reactions nor the Calvin cyclee. occurs in the chloroplast but is not part of photosynthesis

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants.

Produces NADHa. light reactions alone b. the Calvin cycle alonec. both the light reactions and the Calvin cycled. neither the light reactions nor the Calvin cyclee. occurs in the chloroplast but is not part of photosynthesis

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants.

Produces NADPHa. light reactions aloneb. the Calvin cycle alonec. both the light reactions and the Calvin cycled. neither the light reactions nor the Calvin cyclee. occurs in the chloroplast but is not part of photosynthesis

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants.

Produces three-carbon sugarsa. light reactions aloneb. the Calvin cycle alonec. both the light reactions and the Calvin cycled. neither the light reactions nor the Calvin cyclee. occurs in the chloroplast but is not part of photosynthesis